The marked elevation in the incidence of coronary heart disease (CHD) after menopause in women has been associated with increases in total body and visceral fat levels, reductions in aerobic fitness, and adverse changes in other risk factors. Intervention with exercise or dietary restriction alone does not appear to effectively and uniformly improve these CHD risk factors in obese women. The primary experimental goal of the proposed study is to test the hypothesis that a program of combined regular aerobic exercise and moderate dietary restriction reduces total body and visceral fat levels, increases aerobic fitness, and favorably modifies other risk factors for CHD in obese postmenopausal women. An important secondary aim will be to determine if the favorable modifications in these CHD risk factors are associated with the corresponding improvements in body fat and aerobic fitness. Following screening and initial testing, 80 otherwise healthy obese postmenopausal women will be randomly assigned to a 26-week period of either combined regular aerobic exercise and moderate dietary restriction (intervention) or attention control (stretching and light calisthenics). Measurements including resting metabolic rate, dietary intake, total body and visceral fat levels, aerobic fitness, blood pressure, serum lipid and lipoprotein concentrations, glucose tolerance, and insulin sensitivity will be made at baseline, 13 weeks and 26 weeks. The results of the proposed study should provide new and clinically important information concerning the efficacy of this combined intervention in lowering the risk of CHD in obese postmenopausal women. This is important in light of the elevated incidence of CHD in this understudied population.